In high-integration rewritable nonvolatile semiconductor memory devices, the high integration of the memory cells has been promoted using microfabrication technologies and three-dimensional structuring technologies to thereby increase the storage capacity. Meanwhile, processing variation due to the miniaturization and the three-dimensional structuring has been actualized to affect the performance and the operational stability of the memory cells.
There has been known the fact that weak program is performed after erasing data to control the threshold voltage of the erased data. In the case of performing such weak program, it is also necessary to suppress the variation in the threshold voltage caused by the variation in structure of the memory cells.